It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "The Qur'an was revealed in three places: in Makkah, in Madinah and in al-Sham."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7686